In recent years, in semiconductor manufacturing processes, due to high integration and high performance of elements, there has been a demand for additional improvements in fine processing techniques. As semiconductor manufacturing processes, an etching technique is an important fine processing technique, and, in recent years, among etching techniques, a plasma etching technique which has a high efficiency and enables fine processing of a large area has become mainstream.
This plasma etching technique is one of dry etching techniques in which a fine pattern is formed in a solid material by forming a mask pattern on the solid material, which is a workpiece, using a resist; introducing a reactive gas into the vacuum where the solid material is supported in the vacuum; applying a high-frequency electric field to the reactive gas so as to make accelerated electrons collide with gas molecules and form a plasma state; reacting radicals (free radicals) and ions generated from this plasma with the solid material; and removing the reaction products.
Meanwhile, there is plasma CVD which is a thin film-growing technique in which raw material gases are combined using the action of plasma, and the obtained compound is deposited on a substrate. This method is a film-forming method in which a high-frequency electric filed is applied to a gas including raw material molecules so as to form plasma discharge, and the raw material molecules are decomposed using electrons accelerated by the plasma discharge, thereby depositing the obtained compound. A reaction which does not occur only by thermal excitation at a low temperature becomes possible in plasma because gases in the system collide with each other and are activated so as to become radicals.
In this semiconductor manufacturing process, there are processes in which halogen-based corrosive gases, such as fluorine-based corrosive gases or chlorine-based corrosive gases, or a plasma thereof are used, and, among the processes, a fluorine-based gas, such as CF4, SF6, HF, NF3 or F2 or a chlorine-based gas, such as Cl2, SiCl4, BCl3 or HCl, is used in the processes of dry etching, plasma etching, and cleaning.
In the semiconductor manufacturing apparatus in which plasma is used, such as a plasma etching apparatus or a plasma DVD apparatus, an electrostatic chuck apparatus has been thus far used as an apparatus in which a wafer is easily attached and fixed to a specimen table, and the wafer is maintained at a desired temperature.
However, in a plasma etching apparatus of the related art, when plasma is irradiated on a wafer fixed to an electrostatic chuck apparatus, the surface temperature of the wafer increases. Therefore, a cooling medium, such as water, is made to circulate in a temperature-controlling base portion of the electrostatic chuck apparatus so as to cool the wafer from the bottom in order to suppress an increase in the surface temperature; however, at this time, a temperature distribution is generated in the surface of the wafer. For example, the temperature becomes high in the central portion of the wafer and becomes low at the edge side portions.
The difference in the in-plane temperature distribution is caused by the difference in the structure or system of a plasma etching apparatus and the like.
Therefore, a heater function-embedded electrostatic chuck apparatus having heating members attached between an electrostatic chuck portion and a temperature-controlling base portion is proposed (Patent Document 1).
This heater function-embedded electrostatic chuck apparatus can generate a local temperature distribution in a wafer, and therefore it is possible to efficiently carry out local film forming or local plasma etching, such as forming a pattern on the wafer, by setting the in-plane temperature distribution of the wafer in accordance with the film deposition rate or the plasma etching rate.